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found oil on the floor, grounded

A5555

Well Known Member
I had been weeping some oil at the front end and had contacted Superior with pictures but it was inconclusive until today. I walked into the hangar and found oil on the floor and more on the cowl. I am grounded.

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I don't know. There is also an o-ring on the constant speed prop. Suspect it is a front crank seal or the constant speed prop seal.
 
Oil leak

Not good! Not trying to be funny but with that much oil leaking shouldn't be hard to find. Looks to be maybe Propeller to crankshaft area which in sealed via a O-ring. Also appears to be a Whirlwind Propeller?
 
I couldn't remember if you had a CS prop or not. I'm betting prop seal, based on how it was able to pool on the edge of the air intake of the cowl. Crank front seal is too far back, but was the only idea if the prop was FP.
 
Looks like the crank seal. Check to see if there's oil pooling inside the ring gear hub.
I replaced my split crank seal on my superior io360 at about year 2. I'm now in year 10.5 without it leaking. I replaced it with a non-split variety.
It's fairly easy to replace as I was surprised how it stretched over the ring gear hub.I sealed it with pliobond as recommended by the lycoming manual.

Update: I have a fixed pitch prop
 
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Looks like the crank seal. Check to see if there's oil pooling inside the ring gear hub.
I replaced my split crank seal on my superior io360 at about year 2. I'm now in year 10.5 without it leaking. I replaced it with a non-split variety.
It's fairly easy to replace as I was surprised how it stretched over the ring gear hub.I sealed it with pliobond as recommened by the lycoming manual.

I saw oil inside the ring gear hub but not on the fwd side.
 
If it is a crank seal, do check your crankcase vent......

have fun winding that spring...........:eek:
 
Houch! I hope the surgery will be minor to stop the bleeding Steve. Please report back. Is your hangar heated?
 
Houch! I hope the surgery will be minor to stop the bleeding Steve. Please report back. Is your hangar heated?

yep, the Kerosene burns brightly. I must admit I'm timid about doing but I will give it a try.
 
sounds correct to me

If it is on the back side of the ring gear and inside the lip on that side it would tend to be a front crank seal. if it were on the front side of the ring gear hub then it would point to a prop leak. Sorry about the bad news, you can do it.
Yours, R.E.A. III #80888
 
I couldn't remember if you had a CS prop or not. I'm betting prop seal, based on how it was able to pool on the edge of the air intake of the cowl. Crank front seal is too far back, but was the only idea if the prop was FP.

the oil is a significant distance from the front edge of the top cowl. it seems the oil travels fwd and out between the cowl and spinner but I didn't have any oil on the windshield but I did see some on the top side of the cowl at the fwd edge. the dipstick measured 7 qts. so plenty of oil remaining.

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frustrating

I went through months and months of searching for an oil leak. Oil was everywhere but I was "sure" it was the crankshaft oil seal. So I "diapered" the area with some kraft paper that fit around the crankshaft and ran the engine. No oil found. But I removed the (fixed pitch) prop and changed the crankshaft oil seal anyway. Changing the seal wasn't that difficult (My engine uses a split seal). I still had the oil leak so I added some of that fluorescent dye to the engine oil and used an UV flashlight to look for leaks. After hours and hours, I couldn't find any indications.

To make a long story longer, I eventually found some fluorescent dye on the cowling below cylinder #2. The leak turned out to be at the rocker cover gasket but the air flow in the cowling pulled it up front by the ring gear.

May the force be with you.
 
There seems to be more oil on the floor than could drool down from the cowl. Meaning maybe like something that contains oil is leaking. If that much oil was simply splattered around on the cowl, the belly would have been covered, I'd think.

Good luck! Two types of engines - those that have and those that will leak oil...
 
Seal Tool

My front seal started leaking in my Superior XP engine at about 300 hours. I replaced it and no more leaks so far at 1100 hours.

Lycoming sells a seal tool to help install the one-piece seals but they are $1150 to $1200. I bought the Aircraft Tool Supply version (5209) for $80 and it worked very well. Took much longer to get the seal seating area completely clean (working in tight space behind the flange) than actually replacing the seal itself.

Andy
 
Steve,
I have a split front seal you can have - but I don't understand how those don't leak...... I had a leaker on my RV6 years ago and I had Jeff at Elite put a new solid one in for me. Took him about 15 minutes. I think he boiled it first to soften it up and then slid it over the crank flange. Then used the Lycoming approved sealant and let it set. Never leaked again. You'll have to take your prop and ring gear off first. Will you be out there tomorrow? (Saturday)
 
That sucks Steve. Best of luck getting back in the air soon. At least it is the c rappy weather time of the year for flying anyway!!
 
Steve,
I have a split front seal you can have - but I don't understand how those don't leak...... I had a leaker on my RV6 years ago and I had Jeff at Elite put a new solid one in for me. Took him about 15 minutes. I think he boiled it first to soften it up and then slid it over the crank flange. Then used the Lycoming approved sealant and let it set. Never leaked again. You'll have to take your prop and ring gear off first. Will you be out there tomorrow? (Saturday)

I'll be out there on Saturday. The "Jeff" approach sounds good to me.
 
Thanks for sharing Steve. Sorry this has happened.

I have a Superior 0360, so far it has no leaks anywhere but I know that can't go on forever.
 
I had a leak on a IO360/Hartzell combination that looked a lot like this. It turned out to be the prop seal. Oil pushed past the seal, past the ring gear, and came out on the back side then was spun out by centrifugal force. Had oil pooled on top of the airbox. I could have sworn it was a leaking crank seal and even got the replacement part for it. When I took off the ring gear and looked the seal was dry. Replacing the o-ring sealing the prop fixed the problem.

You'll know pretty quickly once you get the prop off.
 
Slide your fingers around the back of the ring gear so you can touch the seal, it's tight, but you can do it. Wiggle the prop back and forth, you should feel the seal move a tiny bit if it's leaking from there. There are some things you can mess up with the seal installation and the plio- bond if your not careful. Make sure the case is completely free of old plio-bond and clean it well with solvent. Heat seal in boiling water for a minute to make it pliable. Don't over stretch the spring in the seal, it goes on separately. Put a drop of oil on the crank so no adhesive sticks to it. Don't forget to seat the spring back in the seal. Order two seals, they are cheap and sometimes they break when getting stretched, no often, but they do. Let engine sit for a day to let adhesive fully cure, and wiggle the prop a little till it starts to set, don't want it adhearing to the crank.
 
There seems to be more oil on the floor than could drool down from the cowl. Meaning maybe like something that contains oil is leaking. If that much oil was simply splattered around on the cowl, the belly would have been covered, I'd think.

Good luck! Two types of engines - those that have and those that will leak oil...

I am with Alex here. A front seal will only leak when the engine is running. There is no standing oil in that area after shut down. The amount of oil on the floor is indicative of oil leaking from an area with some volume of oil in it. The prop hub holds a decent amount of oil and I would be looking for a leak there first.

Larry
 
I am with Alex here. A front seal will only leak when the engine is running. There is no standing oil in that area after shut down. The amount of oil on the floor is indicative of oil leaking from an area with some volume of oil in it. The prop hub holds a decent amount of oil and I would be looking for a leak there first.

Larry

I somewhat agree but no one has mentioned the possibility that there was a major seal failure shortly before the airplane was put in the hangar. The cowl interior could have been coated with oil but not really noticed until it had drained out onto the floor.

I agree with a previous post that if if it turns out that the seal has had a major failure, the crankcase venting should be inspected. If your last flight was in below freezing conditions, it could have even be caused by an iced up vent tube.
This is pretty much unheard of with RV's if you do the recommended vent installation but if yous is different it is a possibility. Or if you have the vent connected to the exhaust... it is probably time to inspect and see if it has plugged.

The oil in the prop hub has a path to the nose section of the engine (where the front seal is) so if the seal failure was severe enough I think it is possible for oil in the prop to leak.

I agree that removing the prop is probably the best first step. It will need to be off to fix the cause, regardless which is the source of the leak.
 
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. Or if you have the vent connected to the exhaust... it is probably time to inspect and see if it has plugged.

I know it's been discussed at length, and Allan even has an SB on the separator he sell that plugs into the exhaust, but if you have that you definitely need to check it. As a data point I am currently conducting my first condition inspection and just cleaned mine, with 105 hours of runtime it was somewhere between 1/3 and 1/2 closed off with coked oil. I have an IO360 running mostly WOTLOP with Vetterman crossover.
 
as found, untouched, front crank seal, there's the source of the leak, the seal was completely free of the case, this is a one piece seal not split

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the vent was clear

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some kind of grey sludge in there

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Wow. I would imagine things could have been much worse - seems like that could lose a lot of oil very quickly in flight. Glad you found it.

Chris
 
Gray matter

The gray matter is stuff in the oil being centrifugally separated in that cavity. That is the reason for pulling the prop periodically and cleaning that area.

The 65-70 honda motorcycles and some Fiats had a slinger on the end of the crankshaft that did this job. The material had to be chiseled out if left too long without service.

Glacier.
 
some kind of grey sludge in there

Its lead, you are running a centrifuge there. The lead collects in anything that spins including accessory case gears.

To me it seems like that seal may not have been put in properly as there isn't much sealant and/or the sealant has not stayed on the seal.

The local engine guy we work with recommends 5 minute Araldite for experimental prop seals. He says it works a lot better than the Loaming approved stuff.
 
Rank case seal

The seal may have been pushed out by crankcase pressure due to vent blockage. Cold temps can cause ice to form in vent,so you must have a V notch cut in vent line as alternate outlet if this happens. I saw your vent line is rubber, if it's all rubber, you might consider puttting a section of aluminum tube in for a place to notch it.
 
The seal may have been pushed out by crankcase pressure due to vent blockage. Cold temps can cause ice to form in vent,so you must have a V notch cut in vent line as alternate outlet if this happens. I saw your vent line is rubber, if it's all rubber, you might consider puttting a section of aluminum tube in for a place to notch it.

the lower 8 inches is rubber the other is alum. I do not have a notch in the alum. I do fly when it's cold. the coldest was -27C. something for me to consider.
 
Its lead, you are running a centrifuge there. The lead collects in anything that spins including accessory case gears.

To me it seems like that seal may not have been put in properly as there isn't much sealant and/or the sealant has not stayed on the seal.

The local engine guy we work with recommends 5 minute Araldite for experimental prop seals. He says it works a lot better than the Loaming approved stuff.

humm, it's the same color as lead. where does it come from, the oil or fuel?
 
I, and several others that run the Superior engines, have had front seal failures. We have all found that the front seal was installed with white silicone sealant. I am not sure what you mean by "the same color as lead" but white flakes is what we all had. New seals and plio bond adhesive were the answer.
 
I, and several others that run the Superior engines, have had front seal failures. We have all found that the front seal was installed with white silicone sealant. I am not sure what you mean by "the same color as lead" but white flakes is what we all had. New seals and plio bond adhesive were the answer.

it looks grey like lead but it could be dirty white silicon remnants.
 
Thoughts

I believe the odds are good that the vent froze up and internal pressure pushed the seal out.

Over time all hollow cranks accumulate that sludge in the bore. 500 hrs is a good interval to have a look in there and clean it out.

Any chance the tail pipe is able to rise a little in flight and block off the end of the vent hose? By all means cut or drill a vent opening high up on the vent tube. Look at a couple certified planes to see how they do it.

I've had good results with aviation grade Hylomar as a sealant and I don't use oil any more as a lube when stretching the seal over the crank flange. A plastic grocery bag works great and the big bonus is no oil to clean off the rubber where you now need to put sealant.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
My front crankshaft seal that was installed during the rebuild (prior to hanging the engine) leaked a lot. At the first annual, I decided to replace it. It came out way too easy. The seal was put in with some sort of contact cement (like pilobond). I bought the recommended Dow Corning 737 Neutral Cure silicon sealant and used this successfully on the second seal. That seal leaked still (but not as bad as the first one), so I replaced it again at the second annual. This time it was much harder to pull out the seal, so I can highly recommend using the silicon sealant! I guess the third time is the charm, since this last seal seams to be keeping the cowling on the inside from getting an oily spray around the starter ring. It still isn't completely clean in there, but MUCH better than the previous seals.
 
My front crankshaft seal that was installed during the rebuild (prior to hanging the engine) leaked a lot. At the first annual, I decided to replace it. It came out way too easy. The seal was put in with some sort of contact cement (like pilobond). I bought the recommended Dow Corning 737 Neutral Cure silicon sealant and used this successfully on the second seal. That seal leaked still (but not as bad as the first one), so I replaced it again at the second annual. This time it was much harder to pull out the seal, so I can highly recommend using the silicon sealant! I guess the third time is the charm, since this last seal seams to be keeping the cowling on the inside from getting an oily spray around the starter ring. It still isn't completely clean in there, but MUCH better than the previous seals.

thx. it seems that I should learn how to do this job.
 
There are now three people on our field who have had this problem, including Noel and myself. I built my engine down at their build school (when they were still doing that) and at that time, at least, were using that silicone sealant. It just didn't hold up.

As Noel said .... new seals and plio-bond was the answer.

I, and several others that run the Superior engines, have had front seal failures. We have all found that the front seal was installed with white silicone sealant. I am not sure what you mean by "the same color as lead" but white flakes is what we all had. New seals and plio bond adhesive were the answer.
 
Found oil on the floor, grounded.

Hi Steve: Our MDRA inspectors won't pass a airplane up here unless it has a vent tube attached.

This drawing was sent to me by another builder, I've installed mine per drawing.

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Hope this helps, Terry.
 
the exhaust pipe must be 500F in the area of the vent. the breather hose is burned to contour so I know it's close to the pipe. seems unlikely that ice could develop at this exit but maybe it could develop upstream. my thinking was that hose would better insulate than an alum tube. the hose is about 8 inches long at the bottom, the upper is alum.

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I have to agree!

I have to agree with the gasman this time of year, make sure there's a relief hole in your vent line well above were it can freeze !
 
I have to agree with the gasman this time of year, make sure there's a relief hole in your vent line well above were it can freeze !

what's the vertical temperature gradient at the firewall during cruise flight?

and what about insulating the alum tube?
 
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what's the vertical temperature gradient at the firewall during cruise flight?

and what about insulating the alum tube?

DanH has posted some temperature deltas for ambient-lowercowl-exit, so you can search. In the shrinking exit, maybe. I seem to remember in excess 100F temp rise from ambient to lower cowl. Anything over 52F rise will leave above freezing.
The blow-by exits just above oil temperature (again DanH number). It is very doubtful that you have iced that blow-by tube, especially since the last 8" is hose.

I would (do some research and ) just properly install that seal. No other change.

Edit: DanH's exit link above is with the cowl door closed. Here is some of his early data - it has 90F temp rise from ambient. Conclusion still the same.
 
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Hi Steve: Our MDRA inspectors won't pass a airplane up here unless it has a vent tube attached.

This drawing was sent to me by another builder, I've installed mine per drawing.

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Hope this helps, Terry.

This pops up occasionally...

To arbitrarily say that all airplanes should have whistle holes in their vent tubes shows a lack of understanding of the issues involved.

Years ago there were accidents that resulted from frozen vent tubes causing high crank case pressure and blowing our crankshaft seals. There were even AD's issued by the FAA on certain airplane models because of it, but the FAA has never recommended an across the board compliance.
The reason for this is because the airplanes that had the problem had their vent tubes protruding out into the slip stream.

I am not aware of a single incident with any RV where a frozen vent tube was suspected as a cause, if the installation was done per the plans with the tube up inside the cowl. This keeps the entire tube in an area too warm for ice to form.

If the standard per plans method was at risk for freezing, I think we would have had hundreds of blown out crankshaft seals on RV's by now.
 
The seal was put in with some sort of contact cement (like pilobond). I bought the recommended Dow Corning 737 Neutral Cure silicon sealant and used this successfully on the second seal. That seal leaked still (but not as bad as the first one), so I replaced it again at the second annual. This time it was much harder to pull out the seal, so I can highly recommend using the silicon sealant! I guess the third time is the charm, since this last seal seams to be keeping the cowling on the inside from getting an oily spray around the starter ring. It still isn't completely clean in there, but MUCH better than the previous seals.

If by recommended you mean by Lycoming, I am pretty sure that the number 1 product recommended by them is a pliobond adhesive.
 
DanH has posted some temperature deltas for ambient-lowercowl-exit, so you can search. In the shrinking exit, maybe. I seem to remember in excess 100F temp rise from ambient to lower cowl. Anything over 52F rise will leave above freezing.
The blow-by exits just above oil temperature (again DanH number). It is very doubtful that you have iced that blow-by tube, especially since the last 8" is hose.

I would (do some research and ) just properly install that seal. No other change.

Edit: DanH's exit link above is with the cowl door closed. Here is some of his early data - it has 90F temp rise from ambient. Conclusion still the same.

thanks. that's my plan and I will the measure the exit temps to confirm.
 
My most recent temp measurements last summer showed 170-ish *F temp lower cowl temps during cruise at 80-90 *F OAT which would coincide with the 100* above ambient. I can try to grab some addition temps in sub-freezing wx but I'm certain the lower cowl temps anywhere inside the loser cowling will still be above 100*F.
 
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